I think you have gone about this the wrong way toby.
I have a friend who breeds for a hobby she has 4 girls and 2 boys and she has been doing this for a good while now.
I asked her what she does with her cats after they have forfilled their purpose they are the exact words i used I was thrown out of her house n was told I would be lucky if she ever spoke to me again!
I like you had strong opinions on breeders and what they do with their extra cats etc and I had to take a good hard look at myself because without meaning to I had judged a life long friend.
If you find a good breeder they will do everything they can to make sure their cats are well looked after I have even found some breeders take care of ALL of their cats better than i take care of my 3 moggies
It would be daft if a breeder kept all their cats and as long as they are privatley rehomed to good decent cat lovers i dont see the problem anymore.
Take it from someone who was exactly like you, the attitude you have is very niave ad i suggest you become friends with a breeder before you judge them x